Enter the number of options and then how many you need to choose, and the Combination Calculator will let you know how many options you have. So if you have to invite only a subset of your friends to party, this will tell you exactly how many ways you can offend people.

Just for kicks, we’ve also included the number of was to choose if you include permutations (the ‘pick’ function). Should you care about exactly what order those people stand in while at your party. And we’ve even thrown in the factorial of the of the original number (because it was, like, one extra line of code). This tells you how many ways to order the full set.